Heating plant



Jam,

J. A. SHERMAN ET AL.

HEATING PLANT Filed July 8, 1918 4 Sheets-Sheet l .Fam 20), F925.l,523,564

J. A. SHERMAN ET AL HEATING PLANT Filed July 8, 1918 4 Sheets-Sheet 2Jaun. 20, H925. l

J. A. SHERMAN ET AL HEAT ING PLANT Filed July 8, 1918 4 Sheets-Sheet :5

F/g f4 y :J- 4 aff V /ff 'jm 205. H925.

J. A. SHERMAN ET AL HEATING PLANT Filed July 8, 1918 4 Sheets-Sheet 4@gf-f Patented dan. 20, i925.

Nrrao JOHN A. SHERMAN AND WILLIAM H. SHEPIPARD, 0F WORCESTER,MASSACHUSETTS; SAID SHEPIARD ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS,O'F HIS RIGHT TO WILLIAM J'. WOODS, OF WORCESTER, MASSACHUSETTS.

HEATmG PLANT.

Application led July 8, 1918. Serial No. 243,875.

To all who-m t may concern.'

Be it known that we, JOHN A. SHERMAN and WILLIAM H. SHEPPARD, both ofWorcester, in the county of Worcester and State of Massachusetts,citizens of the United States, have invented a new and 4usefulImprovement in Heating Plants, of which the following is aspecification.

The purpose of our invention is to provide a heating plant for householdor other use, which in its preferred and complete form is automat-ic,that is, it will maintain the house at a given temperature during thewhole twenty-four hours of the day, or will reduce the temperaturetemporarily for any predetermined period. This and other featureshereinafter described may be carried out. by the apparatus shown in thedrawings. Certain of the instrumentalities are old and well known in theart, being easily procurable on the market and hence are not describedin detail.

In the drawings in which the invention is shown in its preferred form-Figure l is an elevation showing the apparatus as a wholediagrammatically.

Fig. 2 is a section of the burner and its feeding tank.

Fig. 3 is an enlarged side elevation of the relay J, and

Fig. 8 is a front elevation thereof.

Fig. ll is a side elevation of release switch K.

Fig. 5 is a diagrammatic View in plan of the time switch, and Fig. 6 isa similar View showing the snap switch and its mounting.

A is an oil reservoir of any convenient size, for example, large enoughto contain a supply of oil or other liquid fuel cap-able of lasting saysome weeks or months. While we have shown one such tank, the number ispurely a matter of convenience. It is provided at A1 with a suitableopening for filling. A2 is a gauge to show the height of oil in thetank. y

D is the oil pressure tank vwhich is fed by gravity from the tank Athrough the pipe a whenever the pressure inftank B is sufficiently low,this tank preferably holding a dayls supply of fuel. The pipe (Lcontains a check valve 011 to prevent the oil in the tank B from buckinginto the tank A when under pressure.

airtight. vIt is supplied with oil from the v tank B by the pipe b. Avalve b1 located in the pipe may be used to cut off the oil supply tothe tank C when desired. The pipe Z) terminates in a valve c located insaid tank C (see Fig. 2) and controlled by the lever c1, rod c2 andfloat o3, the whole being adjusted to maintain the oil c4 in the tank atthe desired height, operating after the manner of the ordinary ballcock.

D is the casing of the burner. It has a neck D1 by which it is supportedin an opening in the cover of the tank C. AXially mounted in the casingD is the fuel nozzle d, which has a passage cl2 running partly throughit connected .by the opening ci with a longitudinal passage in the neckD1, which latter passao'e is connected with the passage in the pipe 2running nearly to the bottom of the interior of the tank C.

The casing D has a jet opening d1 which registers with the opening d3 inthe tip of the nozzle d.

The rear end of the nozzle beyond the opening als is solid and isthreaded and passes outside the rear end of the casing D through a nut(Z4 which is so attached to the casing as to turn thereon and by turningadjust the location of the tip of the nozzle d with relation to the jetopening. A screw Z5 sets into a longitudinal groovein the nozzle so asto keep it from turning with the nut while adjustment is being made.

The opening d is sufliciently long to keep in register with the openingin the neck D1 however the nozzle may be adjusted.

Between the casing D and the nozzle Z is an air chamber f1 whichsurrounds the sides of the nozzle and its tip and is supplied withcompressed air by the pipe f which lea-ds into it from the air pump F.The oil is drawn up from the tank C by suction due to the passing out ofthe compressed air from the chamber f1 through the opening d1 and pastthe tip d3 of the nozzle, the whole acting after the manner of anatomizer.

A passage f2 leads from the chamber f1 to the tank C and supplies airunder pressure to the surface of the oil in the tank so as to assist inlifting the oil to the nozzle as well as to supply the place of the oilas it is withdrawn. By adjusting the nozzle longitudinally as abovedescribed the amount of the oil feed will be adjusted in the well knownway.

E is the casing of the firebox of the heater and it is provided with adoor E1 in which an opening is located registering withthe opening Z1 inthe end of the burner Acasing so that the flame from the burner will bethrown into the firebox (see Fig. 2). E2 is the covering for a peep holeby which the flame may be inspected and e is a pilot light mounted on-the outside of the Firebox near` the burner D and connected to the gassupply of the burner.

The air pressure in the tank C will balance the pressure in the tank Bso that t'hc oil will flow from B to C by gravity. Thel pressure in thetank B will prevent oil from fiowing from A to B except when thatpressure is reduced sufficiently, for example, when the pump F is idle.f

The oil is thus drawn from the tank C to the burner by compressed airacting chiefly by suc-tion so that the more pressure given to the air,the better vacuum is created and the more oil is lsucked up. It has beenfound that under usual conditions more perfect combustion is secured inthis way wheny the parts D and d are properly adjusted with relation toeach other, the air determiningvthe amount of flame thrown into thefirebox.

An additional advantage of this construction lies in the fact that whenthe air ressure is shut off', the oil settles back om the burner intothe tank, thus avoiding any leakage or overflow of oil into the-iirebox.

Compressed air is supplied to the pipe f by the air pump- F operated bythe electric motor G. The pipe f runs from the air pump to the coup-lingF1 from which it supplies pressure to the oil in the oil pressure tank Band from thence to the casing D and also to the tank C by the passage f2as above described.` Thus the flame is controlled by the air pressureat'the burner,.

which sucks up the oil into the burner and atomizes it, and the air pumpF which gives this pressure is controlled by the motor Cr. Thestoppageof the motor, therefore, momentarily or otherwise, stops'thesupply of fuel so that the flame is extinguished. To relight it thepilot burner e is preferably used. I i..

The motor G as sho-wn is in a loop from the main electric circuit of thehouse independent of the lighting circuit and its circuit is controlledby a thermostat located in any desired part of the house, say the livingroom or hall, the arrangement being such that when the housetemperature. has reached a predetermined high degree the motor circuit`is broken so that the motor stops, thus stopping the ump and the fuelsupply to the burner. hen the temperature has dropped to a predetermineddegree, the' circuit is again closed and the motor starts up the pump tofeed fuel to' The return wire 2 from the motor is connected to a bracket3 mounted on base 300 of insulating material at the relay J. Theelectro-magnet 15 of the relay is operated automatically by a circuitincluding the thermostat H, as will be explained later.

The relay comprises the electro-magnet 15 which has an armature 17pivoted at 152 to a bracket 1 81 and terminating in a latch 171 whichnormally engages and holds up a lever 18, also pivoted to the bracket181 mounted on the base 300, but electrically insulated from saidbracket as indicated by Washers 182 in Fig. (3a. This lever 18 isslotted and is normally held in the position shown in Fig. 3 by thelatch 171 at the end of the armature 17 against the force of a spring 19attached to it and the sup-- port 3 which passes through the slot in thelever 18. The attraction of the armature 17 by the energization of coil15 will lift the latch 171 from engagement with the lever 18 and thespring 19 will throw the lever 18 out so that the latch 171 and leverand springs 19 and support 3 become: separated, thus breaking thecircuit at this point.

The circuit is normally by wire 2 to bracket 3, expansion spring 19,lever 18, latchl 171, bracket 181 and wire 4 to the release switch K.The Wire 4 is attached to the bracket 181 through Athe base 300 y in anyconvenient way.

The relay Ll is controlled by a thermostat H of usual construction incircuit with the electro-magnet 15. Its thermostatic arm 10 is connecteddirectly by wire 9 with the main wire X. Two terminals 11 and 20 areprovided, with either of which the arm construction, wire 14;, ,to thecoil 15 of thel electromagnet, from whence this circuit proceeds throughthe wire 16 to the main line Y.

' The energizing of the coil 15 attracts the armature 17 the lever 18and allows the spring 19 to push out the lever 18, thus breaking themotor circuit and causing the motor to stop .so that the latch 171releases` and stop the pump, cutting off the supply ot oil from theburner at the boiler.

As the house becomes cooler the arm 10 resumes its neutral position andthen moves over until it makes contact with 20 thus establishing thecircuit from line X through wire 9, arm 10, contact 20, wire 21, timeswitch 13, wire 22, to coil 23, thence by wire 24 to the main line Y.The lever 18 acts as an armature to be attracted by the coil 23 andhence, when this coil is energized, the lever 18 is attracted and theparts 117 and 18 re-engage, thus re-establishing the 'main circuit fromthe relay J by wire 4, re-

lease switch K, wire 6, etc. to the main line Y, so that the motor isagain energized, starting up the pump and the oil circulation.

If after the motor circuit has been broken it is again closed as abovedescribed the pilot light relights the fuel at the burner. If, however,the pilot light has accidentally been extinguished, while the burnerwill again be supplied with fuel, the fuel will not bel ignited, butwill flood the rebox which will be cooling oli'. The main purpose of therelease switch is to give an alarm under such conditions. 400 ofinsulating material on which is mounted a switch 5 normally engaging theswitch point k1 to which wire 4 is connected.

This switch 5 is of usual knife` blade construction and is hinged at l:to a conducting member mounted on the base 400 and electricallyconnected with the wire which runs to a snap switch 7 and is continuedby wire 8 to wire Y of the house circuit.

On the base 400 is also hinged an armature 34 controlled `by anelectro-magnet 32.

Against this armature 34 rests a circuit controller 35 on one end of aninsulated push rod 351 which rod is slidable through the base 400, itsother end contacting with the free end of the switc'h 5. Upon theenergizing of the coil 32 the armature 34 is attracted, thus releasingthe controller 35 and allowin a spring k2, one end of which is attacheto the controller and the other end connected to the base 400, to pullthe controller 35 toward the base 400, thus causing the push rod to pushswitch 5 out from its contact with k1 into the position shown in dottedlines in Fig. 4 and breaking the circuit.

At the same time 35 makes contact with i terminal 361. This terminal isconnected by wire 36l with an alarmvv bell N which is also connected byWire 37 with the main line X. The controller 35 being connected by wire38 with the main line Y, when 35 comes in contact with the int 361 acircuit is closed through the bell and the bell rmgs.

The coil 32 is in circuit with a thermostat P controlled by thetemperature in the firebox. It comprises a the-rmostatic arm 26 Itcomprises a base which is connected with the main line X by the wire 25and a contact 27 arranged in such a manner thatwhen the temperature getsbelow a certain point due, for example, to the accidental extinguishingof the pilot light, the arm 26 will make contact with contact 27. Thecontact 27 is connected by wire 28 with a terminal 29 adapted to contactand normally contacting at the compressed air motor R with a terminal30. lhis terminal 30 is connected by wire 31 with coil 32, the lead 33Jfrom which connects with the main line Y, so that when the circuit isclosed at 26 and 27 and at 29 and 30 coil 32 will be energized, itsarmature attracted, and switch 5 thrown out by the release of circuitcloser 35, thus breaking the motor circuit and ringing the alarm bell.

The parts willremain in this condition holding the motor circuit open atthis point until the member 5 is reset by hand, but this cannot be donebecause so long as the circuit through the coil 32 is closed itsarmature will be attracted and the rod 351 will prevent the resetting ofthe switch 5. To break this circuit quickly the contacts 29 and 30 areprovided, the position of one of which, say 30, is controlled bypressure in the air system. This co-ntact 30 is mounted on, andinsulated from a rod g1 carried by a spring diaphragm g which closes theend of a compressed air cylinder Q, this cylinder being connected by afeed pipe g2 to the pipe j' of the compressed air system. Thisconstruction is such that when the air in the cylinder Q is under fullpressure its diaphragm g serving as a compressed air motor is convexedand 29 and 30 are in contact, and when under less pressure it isconcaved and the contacts 29 and 30 are separated, th-us breakinvr thecircuit through coil 32 (see Fig. 1.). 2 is a throttle valve by whichthe admission of air pressure to the cylinder Q may be controlled sothat pressure in cylinder Q will accumulate slowly. Thus when 29 and 30have heen separated by the release of pressure in cylinder Q it willtake an appreciable time after the starting up of the air pump to bringthem again into contact, during which time the burne-r having beenignited will warm the firebox and separate arm 26 from 27.

When the air pump stops owing to the breaking of the motor circuit, airpressure will leak from the whole compressed air system throu h theburner, thus causing the separation'o 29 and 30. When originallystarting the system, the pilot light is lighted and the motor isconnected with the source of current, after which the apparatus operatesautomatically until the pilot light, is

liU

accidentally or intentionally extinguished-5' The snap switch which isconnected by* wire 6 with the release switch K and ,by 'f the wire 8with thehouse circuit wire Y, breaks the circuit when the boilerpressure is too great. It is constructed and operated as follows: Theswitch is mounted on a base plate 81 of insulating material. comprisestwo independent arms 7 4 and 7 5 both of which are pivoted at 71 to thebase plate 81. 72 is a spring which is connected to each of these armsin such a manner as to hold them normally at a slight angle to eachother as shown in Fig. 1. Arod m2 connects the arm 74 with the free endo`f lever m, the other end of the lever being pivotally supported on thepressure motor This'lever rests upon a rod m1 connected toa diaphragm(not shown) in the pressure motor M. Such a motor is of'well knownconstruction such that the diaphragm within it is raised when thepressure in the boiler rises above a certain amount. The diaphragm liftsthe rod m1, lever m and the rod m2 and pushes up the arm 74. Thiscarries the spring 72 over the centre 71 so that it pulls the arm 75 offits contact 73, thus'breaking the connection with the wire 8 which formsthe return circuit to wire Y. Thus when by any accident the pressure inthe heater or boiler has exceeded the safety point', the motor circuitwill be opened and the motor will be stop ed, thusl extinguishing theflame of the burner and allowing the boiler pressure to lower when thesnap switch will be reset. reset automatically by the lowering ofpressure in the boiler and the pressure motor.

We have shown in Fig. 5 diagrammatically what we have termed a timeswitch containing a second thermostat. This second thermostat is in allrespects like the thermostat H, but it is adjusted so that it operatesbetween lower temperatures than the thermostat H, but it is connected toelements whereby it is made operative or thrown into circuit only atpredetermined periods of time, and at other, times it is ineffective, asdescribed below. Thus during the day thermostat H may be usedin whichthe .range of 'temperature may be say between 68 and 70,` y at say 10oclock at night, or at any other desired time, may switch offthis'the'rmostat and switchin another thermostat the range of which maybe'between 40 and42, which This time switch will be understood from 5which it is shown diagrammati-j cally. VOn the base 13, which is ofinsulating material, is mounted-a cam wheel *131' which is preferably.rotated by clockwork making a -single rotation in any desired time, say24 hours. Its swell is sov con- ItA This switch will be` while the timeswitchi structed as to correspond with the proportion of the day orother period during which its thermostat is to be effective. A lever 132pivoted at 133 carries a finger 134 adapted to rest on the edge of thecam, being held against it by the spring 135 one end of which isattached to the arm 132 and the other end to the base 13. The outer endof this lever carries a contact` 13G. It also carries an arm 137 whichis insulated from it, but also carries a Contact 138. The wire 21 isconnected to two contacts, one of which 139 is positioned to receive thecontact136 The wire 21 runs back tothe contact 2O in thermostat H. Thiscontact is the one which the thermostatic arm 10 strikes when thetemperature is below normal. The wire 22 is connected to the arm 132 sothat when the cam is in the position shown, i'. e. during the daytimeand the temperature causes contact between 10 and 20, the circuit isfrom line through wire 9, arm 10 and contact 20, line 21,v throughcontacts 139, 136, lever 132, wire 22 to the relay. When the arm 10 iscaused by the temperature to contact with the contact 11 the circuit isfrom m by wire 9 and arm '10 tol contact 11, wire 12 and wire 14 totherelay J without including the operative parts of the time switch.lVhen the cam has turned so that its swell lifts the lever 132 contactis broken between 136 and 139 and is made between 138 and 231. Thisswitches into the circuit between 9 and the relay J the secondthermostat 233, etc. which controls the temperature between say 40degrees and 43 degrees or whatever temperature the second thermostaticarm 233 is adjusted to. Thereafter the temperature in the house cannotvrise above say 42 'degrees because this second thermostat will causethey motor circuit to be broken when this degree of temperature isreached. The first thermostat H in this case becomes part of the closedcircuit between the wire 9 and the arm 233 of thesecond thermostat234and lil() the second thermostat is cut out of circuit, il whenthecam-131 allows contact to be made again A between 136 and 139. The arm235l j contacts with contact 236 at the lower` temperature and withcontact 237 lat thehigher temperature." Thusthe time switch maybe so setthat'during the night the motor circuit'is controlled b the temperaturejust as in the daytime, ut the temperature is controlled between`different limits. The, cam may be eared to the clock to operate inlonger periods than 24V hours, for exam'- vple, so that a house may beleft over a week# end without danger of the ,water pipes freezing or thefuel being wasted, the shift-` ing 'of the thermostats being adjusted sothat the house will be warm when the occu- Y'pant returns. ,Of coursesuch a time switch may be constructed to operate at desired timesaccording to the requirements of the iituations and circumstances underwhich it s used.

The motor circuit can be traced from the house wire X by wire 1 to themotor G, thence by wire 2 to bracket 3, spring 19, lever 18, latch 171,bracket 181, wire 4 to the release switch member 5, thence by wire 6 andsnap switch pivot 71, arm 75, contact 73 and wire 8 to return wire Y.This line is broken when the thermostat H or the thermostat in time.switch 13 closes the circuit through the wire 14 which leads toelectromagnet 15 and by wire 16 to the return wire Y, in which case thearmature 17 is attracted and moves the latch 171 so that it releases thelever 18 which is pushed out by the spring 19. This it will be seenbreaks the motor circuit at 171 and 18. The lever 18 is again reset bythe operation of the thermostat closing the circuit through 22,electromagnet 23 and wire 24 which is a return to the wire Y.

If the pressure in the boiler be too great the snap switch operates toopen the circuit at 73, 75, and if the pilot light goes out, the circuitis closed at 26 and 27 in which case the circuit is from wire X by 25 tothe therf mostat arm 26, contact 27, wire 28, contacts 29 and 30, wire31, electromagnet 32 and return wire 33 to wire Y. 29 and 30 will bo incontact so long as the air pressure is held in the air system by themotor or otherwise and will be thrown into contact when the air pressuresupplies air to the container Q under suilicient pressure to bulge thediaphragm g outwardly as above described. When the thermostat P at 26and 27 closes the circuit electromagnet 32 attracts the armature 34,releasing the catch 35 and breaking the circuit between the switch k1and its contact 5 and at the same time making contact between 35 and 36in the bell circuit which comprises the wires 37, 38, thus ringing thebell N.

The system is thus automatically controlled by controlling the motorcircuit, for

First. When the house is too hot, causing it to start up again when thehouse cools again to a predetermined degree.

Second. When the boiler pressure has exceded a certain limit, and startit when vthe pressure has gone down. i

Third. When it is desired to keep a lower temperature for a given lengthof time, say during the night or for a day 0r more if absent from thehouse for a visit, after which the motor circuit is closed again.

Fourth. It will also give an alarm 'when the pilot light is out or thesupply of oil is exhausted so that the burner cannot suppl 'will'o'ccurto those skilled in the art.

`What we claim as our invention is 1. In a heating system, a burner, ana1r pump, and connections whereby said pump will supply fuel tosaidburner, and electrical means for operating said pump comprising anelectric motor and a circuit therefor comprising a source of current anda relay-operated switch, a latch normally engaging said switch to holdit in closed position, an electro-magnet adapted when energized todisengage said latch from said switch, and a second electro-magnetadapted when energized to rest said switch, and thermostat circuits eachcontaining one 0f said electro-magnets, also` comprising a singlethermostat arm whereby when said thermostat is under the influence of apredetermined degree of heat said varm will close the circuit throughsaid latch-disengaging electro-magnet, whereby said motor circuit willbe broken and when said arm is under the influence of a predetermineddegree of cold it will close the circuit through the secondelectro-magnet whereby said switch will close said motor circuit andsaid latch will rey-engage said switch.

2. In a heating system, a burner, an air pump, and connections wherebysaid pump will `supply fuel to said burner, and electrical means foroperating said pump comprising an electric motor and a circuit thereforcomprising a source of current and a relay-operated switch, a latchnormally engaging said switch to hold it in closed position, anelect-ro-magnet adapted when energized to disengage said latch from saidswitch, and a second electro-magnet adapted when energized to reset saidswitch, and thermostat circuits each containing one of saidelectro-magnets, said thermostat circuits also comprising a singlethermostat arm whereby when said thermostat is under the influence of apredetermined degree of heat said arm will close the circuit throughsaid latch-disengaging electro-magnet, whereby said motor circuit willbe broken and when said arm is under the influence ofa predetermineddegree of cold it will close the circuit through the secondelectro-magnet whereby said switch will close said motor circuit andsaid latch will re-engage said switch, in combination with a heatercomprising a fireboX located to be heated by said burner, and a heaterpressure motor adapted to be operated by changes of pressurein theheater, said motor circuit also comprising a second switch normally7closed and operable by said pressure motor whereby when the ressure insaid heater exceeds a vpredetermined amount said pressure-operatedswitch will be opened to open said motor circuit and thus cause thestoppageof the pump and the :feeding of fuel to the burner,

said thermostat circuits for comprising asource of current and va,

relay-operated switch, a latch normally engaging said switch to hold itin closed position, an electro-magnet adapted when energized todisengage said latch from said switch, and a second electro-magnetadapted when energized to reset said switch,and thermostat circuits eachcontaining one of saidelectro-magnets, said thermostat circuits alsocomprising a single thermostat arm whereby when said thermostat is underthe influence of a predetermined degree of heat said arm will closethecircuitthrough said latch-disengaging electro-magnet, whereby saidmotor circuit will be broken and when said arm is under the influence ofa predetermined degree of cold it will close the circuit through thesecond electro-magnet whereby said switch will close said motor circuitand said latch will re-engage said switch, in combinaton with a heatercomprsing a iirebox located to be heated by said burner, and a heaterpressure motor adapted to be operated by changes of pressure in theheater, said motor circuit also comprisin al 'second switch normallyclosed and opera. le

by said pressure motor whereby when the pressure in said heater exceedsa predetermined amount-'said pressure-operated switch will be opened toopen said' motor circuit and thus cause thestoppage of the pump and thefeeding of fuel tothe burner, and when the pressure in the heater hasbeen reduced below said predetermined amount said pressure-o eratedswitch will again be closed, and sai pump become operative.

4. In a heating system, a tirebox, a burner located to heat it, an airpum and connections .whereby sald pum wi supply fuel to sa1d burner,electrica means for voperating said pump comprising an electric motorand a circuit therefor comprising a source of current and arelease.switch and means for throwing said release switch to break said circuitcomprising an electromagnet and a circuitvtherefor including athermostat located to be operated by the temperature of the Iirebox,said thermostat normally opening said electro-magnet circult but adaptedwhen the temperature of the iirebox goes below-a predetermined dey greetoA close said electro-magnet circuit whereby-said electro-ma et will beenergized and. cause said re ease switch to be thrown to open said motorcircuit.

A5. In a heating system, a frebox, a burner located to heat it, an airpum and connectionswhereby said pum supply fuel to said burner,electrical) means for operating 'said pump comprising an electric.

including an e motor and a circuit therefor comprising a source ofcurrent and a release switch and means for throwing said release switchto break said circuit comprising an electromagnet and a circuit thereforincluding a thermostat located to be operated by the temperature of thefirebox, said thermostat normally opening said electro-magnet circuitbut adapted when the Vtemperature of the firebox goes below apredetermined degree to close said electro-magnet circuit whereby saidelectro-magnet will be energized and cause said release switch to bethrown to open said motor circuit, in combination with a circuit closerlocated in said electro-magnet circuit, and means comprising acompressed air motor, and connections with said lair pump, whereby whensaid motor circuit is closed said pump will -be energized and willenergize said air motor and cause it to bring one member of said circuitcloser into contact with the other member and maintain them' in contact.

6. In a heating system, a rebox, a burner located to heat it, an airpump and connections whereby said pump will supply fuel to said burner,electrical means for operating said pumpv comprising an electrlc motorand a circuit therefor comprising a source of current and a releaseswitch and means for throwing said release switch to break said circuitcomprising an electromagnet and a circuit therefor including athermostat located to be operated by the temperature of the irebox, saidthermostat normally opening said electro-magnet circuit but adapted whenthe temperature of the firebox goes below a predetermined degree toclose said electro-magnet circuit whereby said electro-magnet will beenergized and cause said release switch to be thrown to open said motorcircuit, in combination withl 'a circuit, closer located in saidelectro-magnet circuit, and means comprising a compressed air motor, andconnections with said air um whereby when said motor circuit is c osesaid pump will l be energized and will energize said air motor and causeit to bring one member of said circuit closer into lcontact with theother member `and maintain them in contact, said connections-comprisinga throttle valve,

burner, a firebox and electrically-contro led means forsupplying fuel tosaid burner ectric circuit, a release switch insaid circuit, means v-foroperating said release switch comprising a' rod, an electrically-oerated alarm, a circuit ytherefor norma y open, a circuit closer,one'terminal thereof being connected Ito said rod to be operatedvthereby when said rod is released,

naeaaca a latch adapted to hold said rod normally in retracted positionwhereby said release switch will remain closed, and means for operatingsaid latch comprising an electromagnet and a circuit therefor includinga thermostat adapted to close said electro- `magnet circuit when saidrebox is cold whereby when fuel is not ignited at the irebox said rodwill operate said release switch and will also cause the closing ofsaidalarm circuit to operate said alarm.

8. lna heating system, an air pump, an

electric motor connected thereto, a circuit for said motor comprising arelay-operated switch having two coils, a thermostat circuit comprisinga heat-controlled arm and two terminals, each terminal being connectedto one of said coils whereby the contact of said thermostat arm with oneof said terminals will close the. circuit through one of said coils andopen the relaycontrolled switch insaid motor circuit and the contact ofsaidlthermostat arm with the other of said terminals will close thecircuit through the other coil and close the relaycontrolled switch insaid motor circuit, in combination with a time switch located in saidthermostat circuit and adapted to out out said thermostat from saidcircuit for a predetermined period of time and substitute fornsaidpredetermined period means :tor opening and closing said motor circuithaving ranges of temperature different from those of said thermostat.

9. rlhe heating system above described comprising a boiler, a lire boxtherefor, a burner to heat said fire box and means for lighting saidburner, electrically-controlled means for supplying fuel to said burnercomprising an electric motor, a circuit therefor and an air pumpoperated by said motor, two circuit breakers located in said circuit,one comprising a thermostat adapted to break the circuit when thetemperature exceeds a predetermined degree and the other lcomprising aswitch and a pressure valve connected to said switch to operate it andlocated to be operated by the pressure in the yboiler when said pressureexceeds a certain amount to move said switch to break its circuitwhereby said circuit may be broken by'texcess of temperature or by eX-cess of'boiler pressure.

l0. The heating system above described comprising a iirebox, a boiler tobe heated 13 from said irebox, a burner and means for lighting it,electrically-controlled means for supplying -tuel to said burnercomprising an electric motor, a circuit therefor and an air pumpoperated by said motor and thermostatic means adapted to open and closesaid motor circuit, and means for opening said moto-r circuit when saidlighting means is operative comprising a pressure motor located to be'operated by the pressure of said boiler, a switch located in said motorcircuit and connections between said pressure motor and said switchwhereby any v excess of pressure in said boiler will cause sald pressuremotor to operate said switch to open said motor circuit.

JOHN A. SHERMAN. WM. H. SHEPPARD.,

